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7.1 | |
10-Mbps and 100-Mbps Ethernet | |
| 7.1.4 | |
10BASE-T |
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10BASE-T was introduced in 1990. 10BASE-T
used cheaper and easier to install Category 3 unshielded twisted pair
(UTP) copper cable rather than coax cable. The cable plugged into a
central connection device that contained the shared bus. This device
was a hub. It was at the center of a set of cables that radiated out
to the PCs like the spokes on a wheel. This is referred to as a star
topology. The distances the cables could extend from the hub and the
way in which the UTP was installed increasingly used stars made up of
stars, referred to as an extended star topology. Originally 10BASE-T
was a half-duplex protocol, but full-duplex features were added later.
The explosion in the popularity of Ethernet in the mid-to-late 1990s
was when Ethernet came to dominate LAN technology.
10BASE-T also uses Manchester encoding.
A 10BASE-T UTP cable has a solid conductor for each wire in the
maximum 90 meter horizontal cable. UTP cable uses eight-pin RJ-45
connectors. Though Category 3 cable is adequate for use on 10BASE-T
networks, it is strongly recommended that any new cable installations
be made with Category 5e or better. All four pairs of wires should be
used either with the T568-A or T568-B cable pinout arrangement. With
this type of cable installation, supports the use of multiple
protocols without rewiring. Figure
Half duplex or full duplex is a configuration choice. 10BASE-T carries 10 Mbps of traffic in half-duplex mode and 20 Mbps in full-duplex mode.
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shows the
pinout arrangement for a 10BASE-T connection. The transmitting pair on
the receiving side are connected to the receiving pair on the attached
device.
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